U.S. patent application number 13/801228 was filed with the patent office on 2014-09-18 for device and method for treating a chronic total occlusion.
The applicant listed for this patent is Mallik Thatipelli. Invention is credited to Mallik Thatipelli.
Application Number | 20140277004 13/801228 |
Document ID | / |
Family ID | 51531040 |
Filed Date | 2014-09-18 |
United States Patent
Application |
20140277004 |
Kind Code |
A1 |
Thatipelli; Mallik |
September 18, 2014 |
Device and Method for Treating a Chronic Total Occlusion
Abstract
A device and method for opening blood vessel blockages, such as
chronic total occlusions, is disclosed. The device has a main body
and motor unit. The main body has an inner tubular member disposed
inside an outer tubular member. The inner tubular member is
reinforced with hydrophilic polymer coated wires, which are drawn
out into two pairs of loops at the distal end of the device. The
motor unit also has an inner tubular member disposed within an
outer tubular member. The motor unit is used to create torque to
rotate the main body having the pairs of loops. When torque
transmitted to main body, the device spins. As the device is
advanced through a blood vessel, the rotating loops penetrate and
break down the occlusion, and recanalizes the blood vessel. Then
device is then exchanged over a guidewire and further therapeutic
interventions can be performed to improve blood flow.
Inventors: |
Thatipelli; Mallik;
(Bakersfield, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Thatipelli; Mallik |
Bakersfield |
CA |
US |
|
|
Family ID: |
51531040 |
Appl. No.: |
13/801228 |
Filed: |
March 13, 2013 |
Current U.S.
Class: |
606/159 |
Current CPC
Class: |
A61B 2017/320733
20130101; A61B 2017/22094 20130101; A61B 2017/22068 20130101; A61B
2017/320775 20130101; A61B 17/320758 20130101; A61B 17/50
20130101 |
Class at
Publication: |
606/159 |
International
Class: |
A61B 17/50 20060101
A61B017/50 |
Claims
1. A vascular drilling device for crossing an occluded blood
vessel, said device having a main body comprising: an outer tubular
member; an inner tubular member interposed within said outer
tubular member; a distal end cap secured to said outer tubular
member and said inner tubular member; a plurality of distal end
loops projecting from said distal end cap for fracturing an
occlusion; and, a plurality of outer loops projecting from said
outer tubular member for fracturing said occlusion, whereby said
distal end loops and said outer loops fracture an occlusion within
a blood vessel when said distal end loops and said outer loops are
rotated and pushed through said occluded blood vessel.
2. The device of claim 1, wherein said plurality of distal end
loops is a pair of distal end loops, and wherein said plurality of
outer loops are a pair of outer loops substantially orthogonal to
said outer loops.
3. The device of claim 1, wherein said plurality of outer loops are
positioned approximately between 0.5 cm and 1.0 cm from said distal
end of said outer tubular member.
4. The device of claim 1 further comprising: at least one wire
helical coil encircling said inner tubular member, whereby said
helical coil improves the strength and flexibility of the said
inner tubular member compared to the strength and flexibility of
said inner tubular member without said at least one helical coil
encircling said inner tubular member.
5. The device of claim 4, wherein said at least one wire helical
coil has a hydrophilic polymer coating.
6. The device of claim 4, wherein said at least one wire helical
coil are two wire helical coils.
7. The device of claim 4, wherein said plurality of distal loops
and said plurality of outer loops are formed from said at least one
wire helical coil.
8. The device of claim 1 further comprising an expandable balloon
configured for inflation, said expandable balloon envelops at least
a portion of said outer tubular member, whereby when said
expandable balloon inflates, said expandable balloon dilates said
occlusion and places said device in a vessel-centric position
thereby substantially preventing unintended entry of said device
into a subintimal plane of said blood vessel.
9. The device of claim 1, wherein said inner tubular member is
characterized by having a central lumen for guidewire exchange, and
said distal end cap is characterized by having a centrally
positioned hole for guidewire exchange.
10. The device of claim 1, wherein said distal end cap is a C-cup
distal end cap.
11. The device of claim 1, wherein said device further comprises: a
motor unit comprising an electric motor; a motor unit inner tubular
member having a threaded outer surface; a motor unit outer tubular
member having a threaded inner surface configured to engage said
threaded outer surface of said motor unit inner tubular member,
said motor unit inner tubular member positioned within an inner
lumen of said motor unit outer tubular member; and, a locking screw
for locking said motor unit to said motor unit inner tubular
member, whereby said electric motor transmits torque to said main
body, thereby rotating said plurality of distal loops and said
plurality of outer loops to fracture said occlusion within said
occluded blood vessel.
12. The device of claim 11, further comprising: a motion sensor
within said main body for measuring speed and character of rotation
of said main body; and, a microprocessor for receiving and
analyzing speed and feedback data; whereby said motion sensor and
microprocessor, in conjunction with an operator's instructions,
allow for better control of said device.
13. The device of claim 1, wherein said main body is characterized
as segmented into a rotationally stationary unit and a drilling
unit: said rotationally stationary unit comprising: a rotationally
stationary unit outer tubular member; a rotationally stationary
unit inner tubular member interposed within said rotationally
stationary unit outer tubular member; a torque transmitting member
interposed within said rotationally stationary unit inner tubular
member, said torque transmitting member distally connected to said
drilling unit; said drilling unit comprising: said outer tubular
member; said inner tubular member; said distal end cap; said
plurality of distal end loops; and, said plurality of outer loops,
whereby only said drilling unit of said main body rotates when said
device rotates, thereby preventing unnecessary frictional forces
against a blood vessel where there is no occlusion.
14. The device of claim 13, further comprising a guidewire tubular
member disposed within said rotationally stationary unit for
inserting a guidewire into a patient.
15. A method of traversing a vascular occlusion using a vascular
drilling device comprising an outer tubular member, an inner
tubular member interposed within outer tubular member, a distal end
cap secured to said outer tubular member and said inner tubular
member, a plurality of distal end loops projecting form said distal
end cap, a plurality of outer loops projecting from said outer
tubular member, the method comprising the steps of: positioning
said device such that the distal end of said device is proximate to
an occlusion; rotating at least a portion of said device for
fracturing said occlusion; and, advancing said device through said
occlusion.
16. The method of claim 15, wherein said vascular drilling device
further comprises an expandable balloon enveloping at least a
portion of said outer tubular member, and further comprising the
step of: inflating said balloon for dilation of said occlusion.
17. The method of claim 15, further comprising the step of:
advancing a guidewire through said device.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to a device and
method for recanalizing blood vessels, and more particularly to a
device and method for fracturing and opening chronic total
occlusions.
BACKGROUND OF THE INVENTION
[0002] Chronic total occlusions (CTO) are vascular lesions that are
totally occluded. These can occur anywhere in the human body such
as coronary, carotid, visceral, iliac, femoral, and popliteal
arteries and veins. Usually these lesions will develop over the
course several months to years. Due to chronicity of their natural
course, there usually will be an adequate amount time to for
development of collateral vessels to supply blood to tissue.
However these collateral vessels barely provide enough blood flow
to keep the end organs alive and are inadequate to support the
function of dependent organs.
[0003] Chronic total occlusions can have serious medical
consequences depending on their location. For example, blockages
located in coronary arteries can cause heart muscle damage and
heart failure, whereas blockages located in femoral and popliteal
arteries can cause leg ulcers and gangrene.
[0004] Chronic total occlusions per se are not "total occlusions",
but rather contain several intrinsic nonfunctional narrow channels.
Traditionally, hydrophilic coated guidewires are used to penetrate
through one or more of these narrow channels to create a contiguous
passage between open vessel segments proximal and distal to
occlusion. This passage is subsequently dilated to accommodate
therapeutic devices such as balloons or stents.
[0005] Various surgical and minimally invasive methods have been in
vogue for many years for revascularization of CTOs. Surgical
grafts, have been for many decades, designed to bypass blockages in
coronary or peripheral vessels. Minimally invasive technologies
include guidewires or CTO devices.
[0006] CTO lesions frequently contain extremely hard and calcified
plaques, which makes them impenetrable. Guidewires, when used in
CTOs, are sometimes risky as they can inadvertently damage or more
ominously perforate the vessel wall. Often, the guidewire tip has
insufficient support, and can buckle during an attempted
penetration into the calcified plaque. The guidewire, when forced
into a CTO, can also inadvertently be misdirected by the operator
in an unintended direction, creating a dead end plane between the
vessel wall and the plaque (i.e. a subintimal plane). If the
guidewire fails to create successful passage through the CTO, the
resulting subintimal tract prohibits the use of subsequent
therapeutic devices such as a balloon, stent or atherectomy
catheter. Another drawback in CTO devices includes shafts that are
not robust enough to resist kinks when advanced inside of a CTO.
Still another drawback is that the CTO device is not easily
controlled, whereby the tip of the CTO device veers eccentrically
away from the center of the blood vessel when the CTO device is
pushed though the CTO. Due to these drawbacks, success rates with
guidewires in CTO revascularization are marginal at best.
[0007] Several CTO technologies have been introduced in an attempt
to overcome some of the difficulties faced when using guidewires
and CTO devices to improve successful CTO penetration rates. In
U.S. Pat. No. 6,599,304 Selmon et al, teach "an intravascular
catheter system for the treatment of occluded blood vessels that
includes tissue displacement or hinged expansion members that are
movable from a closed to an open position . . . . A spreading or
mechanical force may be thus applied to the vessel wall and
occlusion so as to tear, fracture or otherwise disrupt the
occlusion adjoining the vessel wall. This disruption of the
occlusion may create a channel or passageway of sufficient size for
the passage of guidewire or therapeutic catheter around or through
at least a portion of the obstruction as part of an overall effort
to restore regular circulatory function surrounding the occluded
vascular region."
[0008] In U.S. Pat. No. 8,062,316, Patel et al. teach a CTO
catheter with a novel rotating cutting head with helical blades at
its distal end, the tip is lodged in a protective sheath.
"Application of torque to an inner catheter or wire attached to the
cutting head applies spin to the cutting head . . . . Depending on
the angle and nature of the cutting head's protruding blades, the
blades may either may be designed to simply cut through the
occluding material, without actually dislodging the occluding
material from the body lumen, or alternatively the blades may be
designed to both cut through the occluding material, and severe its
links to the body lumen, thereby dislodging the occluding material
from the body lumen."
[0009] In U.S. patent application Ser. No. 11/090,435, Hong teaches
a system for opening CTOs, by using a catheter having multiple
channels. In addition, the catheter may have a bullet-shaped distal
tip and/or torqueing grooves in the proximal and distal shaft,
which will facilitate advancing catheter through CTO with manual
torqueing action at the proximal end. Multiple channels running
along the length of catheter are distensible and used to advance
guidewires, balloons or stents into the lesion.
[0010] In U.S. Pat. No. 8,021,330, McAndrew teaches a novel balloon
catheter with a "no-fold balloon at a distal end thereof that
surrounds a distal portion of a guidewire shaft having a compliant
shaft or tubular section for selectively gripping a guidewire there
within." Upon inflation, the compliant soft section of the
guidewire shaft locks onto the guidewire. "This provides the
clinician a conjoined balloon catheter and guidewire ensemble that
together may be pushed through a tight stenosis such as chronic
total occlusion."
[0011] In U.S. patent application Ser. No. 12/108,921, Duffy et al.
teach a visualization and treatment system for treating CTO. The
system includes an elongated member configured to be tracked to the
chronic total occlusion. The elongated member has a transducer
located at its distal end. Acoustically activated material will be
packed at the distal end of elongated member. The system also
includes an external imaging system constructed and arranged to
create an image of the chronic total occlusion. The external
imaging system may also be configured to generate ultrasonic energy
waves which in turn vibrate the acoustically activated material
located at the distal end of the elongated member. These vibrations
in turn produce mechanical energy that may be used to penetrate and
cross CTO.
[0012] In U.S. patent Ser. No. 13/553,659, Richter teaches an
apparatus and method for guided penetration of chronic total
occlusion. This invention relates to an apparatus that facilitates
accurate placement of guidewire and drilling tip within the blood
vessel during recanalization of CTO. It comprises of an imaging
system which can detect the lesion, vessel wall and guidewire tip
in real-time. "Preferably, this apparatus also facilitates the
penetration of a CTO or other obstruction in a vessel. The method
of using the apparatus of the invention facilitates treatment of
the occlusion and avoids or reduces complications and risks
associated with treating the occlusion, such as perforation of
walls of the vessel and creation of a false lumen."
[0013] In U.S. Pat. No. 7,763,012 Petrick et al. teach a catheter
and method to cross CTOs. The catheter comprises of an elongated
tubular member having a deflectable tip at the distal end. "The
catheter is advanced to a region of interest in an artery proximal
to a lesion. A control wire is operated to direct the deflectable
tip toward the lesion. A guidewire is advanced through the lumen of
the catheter and into the lesion to cross the lesion."
[0014] In U.S. Pat. No. 8,241,315 Jensen et al. teach an apparatus
and method configured to penetrate occlusion while limiting
inadvertent vessel damage. This device includes an elongated sheath
and a stylet disposed within the elongated sheath. The stylet
includes a lumen from proximal to distal ends which will allow
passage of a guidewire after the occlusion is penetrated. In use,
"the stylet can be moved distally such that the distal region of
the stylet penetrates at least partially into the occlusion . . . .
After the stylet has extended through the proximal cap, a guidewire
can cross through the occlusion . . . . Then the recanalization
assembly can be further advanced through the occlusion and the
balloon placed near the distal cap and the stylet centered and
passed across the distal cap."
[0015] Still, success rates with these new technologies are
reportedly varied from 50-70% due to various factors including
operator's experience. In addition, costs, cumbersomeness, need for
complex preparation and lengthy training required for proper usage
of these CTO devices can prohibit their widespread and cost
efficient usage. Hence, despite these technological developments,
there is still a great need for a simple, safe, easy-to-operate,
efficient and cost effective CTO devices.
SUMMARY OF THE INVENTION
[0016] The present invention provides a device and method for
treatment of vascular occlusions. It is an object of the invention
to disrupt vascular occlusions or other blockages formed within
blood vessels in order to provide pathways for the placement of
guidewires, interventional devices and catheters as part of an
overall effort to restore normal circulatory function having the
advantages of a reinforced inner tube, easy controllability and a
shape that prevents vessel damage but maximizes occlusion
fracturing.
[0017] In a first embodiment of the present invention the vascular
drilling device has a main body. The main body has several
components that help direct and mechanically fracture the
occlusion. The device has an outer tubular member. Inside of the
outer tubular member is an inner tubular member interposed within.
At the proximal end of the outer tubular member and inner tubular
member is a distal cap that is sealed to both inner and outer
tubular members. The distal cap preferably is a C-cup that does not
have sharp edges to pierce vascular walls. At the distal end of the
device is a plurality of distal end loops projecting from the
distal end cap of the main body. A plurality of outer loops project
from the outer tubular member proximal to the distal end loops.
When the main body is advanced to the CTO, the operator spins the
main body, either manually or mechanically. The loops on the distal
end mechanically fracture the CTO in front of it. As the loops on
the distal end advance forward into the CTO, the outer loops on the
outer tubular member mechanically fracture the CTO nearer the
vessel walls. Since all the loops have curved edges, even if the
loops touch the vessel wall, it is unlikely that the device will
pierce the vessel wall.
[0018] In one aspect of the invention, the inner tubular member is
reinforced with one or more helically coiled wires. Preferably two
helically coiled wires encircle the inner tubular member in a
double helix fashion and are secured (by polymer glue or another
securing substance) to the outer surface of the inner tubular
member. The helically wrapped wire(s) allows flexibility of the
main body to curve within the blood vessel lumen, and conform to
the pathway of the blood vessel. Having wire(s) encircle the inner
tubular member has the advantage of strengthening the shaft of the
main body, such that the main body will not kink when curving along
the pathway of the blood vessel. The coiled wires also have the
advantage of improving steerability and pushability of the main
body when advanced inside a diseased blood vessel or inside a hard
fibrocalcific plaque of the occlusion.
[0019] In another aspect of the present invention, the device has
an expandable material, such as a balloon, that envelops at least a
portion of the main body and surrounds the outer tubular member of
the main body. The distal end of the balloon is proximal to the
outer loops. Configured in this way, when the balloon is inflated,
the balloon presses against the vessel walls and centers the main
body of the device to the center of the vessel. The use of an
inflatable balloon therefore has the advantage of centering the
main body so that mechanical fracturing of the occlusion occurs
near the center of the vessel, thus preventing unwanted veering of
the main body and distal end of the device into a vessel wall.
[0020] A distal end cap is sealed to the proximal ends of the inner
and outer tubular members, The cap a central hole which creates an
opening from the lumen of the inner tubular member out of the
device so that a guidewire can be inserted within the lumen of the
device and exit through this central hole. The guidewire can be
used for further therapeutic procedures. Additionally, the distal
end cap may have paracentral holes that allow a plurality of wire
loops to project from the cap and fracture the occlusion.
[0021] In another embodiment, the CTO device has a motor unit to
aid in rotating the main body and/or drilling tip. The motor unit
has an electric motor to provide torque to the main body which
spins the pairs of opposing loops to fracture the CTO and threaded
inner and out motor unit tubular bodies. The motor unit is
connected to the main body via these motor unit inner and outer
tubular members. To aid in rotation of main body, the motor unit
tubular members have helically threaded grooved surfaces so that
when an electric motor turns the tubular members, rotational force
can be translated into a linear force, which can drive the distal
end of the device through a CTO. A locking screw may lock the motor
unit to the main body.
[0022] In another embodiment of the invention, the main body is
segmented into two units: a drilling unit and a stationary unit.
The stationary unit can still be linearly inserted and refracted
within the blood vessel, but does not rotate when the motor unit
rotates. Thus the stationary unit is a rotationally stationary
unit. Instead of the motor unit being coupled to the main body of
the device directly, the motor unit is coupled to a torque
transmitting member that is housed within the stationary unit. The
stationary unit has a stationary unit outer tubular member and
inner tubular member.
[0023] The torque transmitting member runs within the elongated
lumen of the stationary unit inner tubular member and connects to
the drilling unit via a coupling member. The drilling unit has the
loops on its outer wall and distal end cap as previously described
above.
[0024] An advantage of the main body separated into a stationary
unit and a drilling unit is that only the small rotating portion of
the main body (i.e. the drilling unit) rotates, instead of the
entire main body rotating. A small rotating unit prevents
unintended damage that may occur if the device rotates against a
vessel wall, which would cause additive frictional forces that
damage vessel walls.
[0025] In one aspect of the stationary unit and drilling unit
embodiment, a guidewire tubule having a guidewire lumen is disposed
between the inner and outer tubular members of the stationary unit,
and a guidewire enters through a proximal hole and exits through a
distal hole of the outer tubular member of the stationary unit. A
guidewire can then be inserted through this lumen and left in the
patient after the device is removed for use in further
treatments.
[0026] In another aspect of the invention a motor sensor is
incorporated into the distal end of the main body of the drilling
unit, and a microprocessor is incorporated into the motor unit. The
microprocessor acquires and analyzes data sent from the sensor
about the motion of the drilling unit, and in turn sends commands
to the motor unit that that operator is guiding. In this way, the
speed and character of rotation of the distal end of the device or
drilling unit can be more precisely controlled by the operator to
suit CTO lesion characteristics.
[0027] A method of traversing a vascular occlusion using the above
stated device is also disclosed. The steps involved in traversing
the occlusion include first positioning the device such that the
distal end is proximate to an occlusion. The distal end of the
device is rotated so that the loops to fracture through the
occlusion. As the device rotates, the operator advances the device
through the occlusion. In one aspect of the method, a balloon
enveloping a portion of the device the device is inflated to center
the device within the blood vessel. The inflated balloon also
presses the occlusion against the vessel wall to minimize the size
of the occlusion. After successfully traversing the occlusion, a
guidewire is passed through the guidewire lumen and the device
exchanged out of the patient so that other procedures can take
place after the device is removed from the vessel.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] FIG. 1A illustrates a front cross sectional view of a main
body of a vascular drilling device.
[0029] FIG. 1B illustrates a front view of the device of FIG.
1A.
[0030] FIG. 1C illustrates a side view of the device of FIG.
1A.
[0031] FIG. 1D illustrates a bottom view of the device of FIG.
1A.
[0032] FIG. 1E illustrates a bottom cross-sectional view of the
device of FIG. 1A.
[0033] FIG. 1F illustrates a front view of the inner tubular member
of the device of FIG. 1A.
[0034] FIG. 2A illustrates a front cross sectional view of the
device of FIG. 1B having an inflatable balloon.
[0035] FIG. 2B illustrates a side view of the device of FIG. 1C
having an inflatable balloon.
[0036] FIG. 3A illustrates a front cross-sectional view of an
alternative embodiment of distal end of a vascular drilling
device.
[0037] FIG. 3B illustrates a front view of the device of FIG. 3A
having a drilling unit and a rotationally stationary unit.
[0038] FIG. 3C illustrates a side view of the device of FIG.
3A.
[0039] FIG. 3D illustrates a bottom cross-sectional view of the
stationary unit of FIG. 3A.
[0040] FIG. 4 illustrates a side cross sectional view of a proximal
end of the device of FIG. 3A.
[0041] FIG. 5A illustrates a side cross sectional view of the motor
unit inner tubular member.
[0042] FIG. 5B illustrates a side view of the motor unit inner
tubular member of FIG. 5A.
[0043] FIG. 6A illustrates a side cross sectional view of the motor
unit outer tubular member.
[0044] FIG. 6B illustrates a perspective view of the motor unit
outer tubular member of 6A.
[0045] FIG. 7A illustrates a side cross-sectional view of a motor
unit inner tubular member interposed within a motor unit outer
tubular member.
[0046] FIG. 7B illustrates a side view the motor unit inner tubular
member interposed within a motor unit outer tubular member of
7A.
[0047] FIG. 8A illustrates a side view of an assembled motor unit
over the main body of the CTO device inserted into a blood
vessel.
[0048] FIG. 8B illustrates a cross sectional view of an assembled
motor unit over the main body of a vascular drilling device.
[0049] FIG. 9 is an exemplary view of a vascular drilling device
inserted through a small hole in a patient's groin, the distal end
of the vascular drilling device approaching an occlusion.
[0050] FIG. 10A is a side cross sectional view of the device of
FIG. 1A within a blood vessel before entering an occlusion.
[0051] FIG. 10B is a side cross sectional view of the device of
FIG. 1A within an occlusion.
[0052] FIG. 10C is a front cross sectional view of the device of
FIG. 1A after passing through an occlusion and after a guidewire
has been inserted.
[0053] FIG. 11 is a front cross sectional view of the device of
FIG. 3A after passing through an occlusion, and after a guidewire
has been inserted.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0054] The invention now will be described more fully hereinafter
with reference to the accompanying drawings, in which embodiments
of the invention are shown. This invention may, however, be
embodied in many different forms and should not be construed as
limited to the embodiments set forth herein. Rather, these
embodiments are provided so that this disclosure will be thorough
and complete, and will fully convey the scope of the invention to
those skilled in the art. Although the description of the invention
is in the context of treatment of blood vessels, the invention may
also be used in any other body passageways where it is deemed
useful.
[0055] It will be understood that when an element is referred to as
being "on" another element, it can be directly on the other element
or intervening elements may be present there between. As used
herein, the term "and/or" includes any and all combinations of one
or more of the associated listed items.
[0056] It will be understood that, although the terms first,
second, third etc. may be used herein to describe various elements,
components, regions, layers and/or sections, these elements,
components, regions, layers and/or sections should not be limited
by these terms. These terms are only used to distinguish one
element, component, region, layer or section from another element,
component, region, layer or section.
[0057] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
the invention. As used herein, the singular forms "a", "an" and
"the" are intended to include the plural forms as well, unless the
context clearly indicates otherwise. It will be further understood
that the terms "comprises" and/or "comprising," or "includes"
and/or "including" or "having" and/or "has," when used in this
specification, specify the presence of stated features, regions,
integers, steps, operations, elements, and/or components, but do
not preclude the presence or addition of one or more other
features, regions, integers, steps, operations, elements,
components, and/or groups thereof.
[0058] Furthermore, relative terms, such as "lower" or "bottom" and
"upper" or "top," may be used herein to describe one element's
relationship to another element(s) as illustrated in the Figures.
It will be understood that relative terms are intended to encompass
different orientations of the device in addition to the orientation
depicted in the Figures.
[0059] The terms "distal" and "proximal" are used in the following
description with respect to a position or direction relative to the
treating clinician. "Distal" or "distally" describe a position
distant from or in a direction away from the operator, and also
refers to the tip of the CTO device closest to the occlusion.
"Proximal" and "proximally" describe a position near or in a
direction toward the operator and away from the occlusion.
[0060] Unless otherwise defined, all terms used herein have the
same meaning as commonly understood by one of ordinary skill in the
art to which this invention belongs. It will be further understood
that terms, such as those defined in commonly used dictionaries,
should be interpreted as having a meaning that is consistent with
their meaning in the context of the relevant art and the present
disclosure, and will not be interpreted in an idealized or overly
formal sense unless expressly so defined herein.
[0061] As shown in FIGS. 1A-1E, the main body 100 comprises two
tubular members: an inner tubular member 11, and an outer tubular
member 10 disposed within the outer tubular member 10. The inner
tubular member 11 has a lumen 38 where a guidewire can be passed
though. Guidewires coated with a hydrophilic polymer are commonly
used for crossing occlusive lesions inside of blood vessels. The
polymer on the guidewire is activated in contact with water, which
makes the guidewire surface highly lubricious and facilitates
advancement of guidewires across narrow cracks and holes contained
inside the atherosclerotic plaque of a CTO. The guidewire can be
used to facilitate the drilling through the CTO.
[0062] Between the inner tubular member 11 and outer tubular member
10 exists an intertubular space 12 which is sealed on both ends of
the main body 100 by a distal cap 15 which may be in the shape of a
C-cup that seals the distal ends of both tubular members 11, 10. In
a preferred embodiment, the inner tubular member 11 is at least 5
mm longer than the outer tubular member 10 such that the C-cup 15
has a depth of at least 5 mm. The curved C-cup prevents sharp edges
from contacting a blood vessel which could possibly damaging the
blood vessel wall 50.
[0063] The outer surface of the outer tubular member 10 may be
coated with a highly lubricious hydrophilic polymer (such as
polytetrafloroethylene or other hydrophilic polymer known to those
having skill in the art) to facilitate free rotational and axial
movement within the healthy or diseases blood vessels. The distal
and proximal ends of the main body 100 and cap 15 may be sealed
with a similar polymer. The main body 100 may be of a variety of
lengths, but preferably, main bodies 100 between 90 cm and 130 cm
are suitable for a majority of clinical applications.
[0064] The outer surface of the inner tubular member 11 is
reinforced with one or more wires. These wires may be coated with a
hydrophilic polymer. As shown in FIGS. 1A, 1E, 1F, 3A, 3B, and 4,
the inner tubular member 11 is reinforced with two hydrophilic
polymer coated wires 13, 14. These wires 13, 14 are wrapped around
the inner tubular member 11 in a double helical fashion.
[0065] In the embodiment illustrated in FIGS. 1A-1E, the distal cap
15 has a central hole 16 that is aligned with the inner tubular
member 11 and provides an exit path for a guidewire to exit through
the central lumen 38. Near the central hole 16 is a pair of
paracentral holes 17 as illustrated in FIG. 1D. Each of the
paracentral holes 17 is approximately 180 degrees from each other
around the circumference of the cap 15 when viewed in cross
section. Proximal to the paracentral holes 17 is a pair of outer
tubular member holes 18. In one embodiment, the pair of outer
tubular member holes 18 is proximally located between 0.5 cm and
2.0 cm from the most distal region of the distal cap 15. In a
preferred embodiment, the pair of outer tubular member holes 18 is
approximately 1.0 cm from the distal cap 15. In the embodiment
illustrated in FIG. 1, each of the outer tubular member holes 18 is
positioned approximately 180 degrees from each other, and the outer
tubular member holes 18 are orthogonally positioned relative to to
the paracentral holes 17. In a preferred embodiment, each of the
outer tubular member holes 18 is approximately 4.0 mm to 5.0 mm
away from each other along the long axis of the outer tubular
member of the main body 100.
[0066] Each of the wires 13, 14 are helically coiled around the
shaft of the inner tubular member 11. The wires 13, 14 are drawn
out through the paracentral holes 17, 18 to form a distal end loops
20, and a pair of outer loops 19. The loops 18, 19 are secured to
the holes 17, 18 with a spot fixing polymer. In some embodiments,
the distal end loops 20 may be oriented slightly inward (not
shown), toward the central axis. Presumably, this orientation will
lessen the chances of vessel wall trauma caused by the distal loops
20 while the device is spinning.
[0067] This type of loop design and configuration where there is a
distal pair of loops 20 pointed toward the occlusion, and outer
loops 19 pointed in the direction of the vessel wall 50 is
advantageous because as the device penetrates and advances through
the CTO, the device will penetrate the CTO proximal cap at four
different locations positioned approximately 90 degrees from each
other at different depths of the CTO.
[0068] In a preferred embodiment, the main body of the device is
approximately 5 mm in diameter at the level of the outer loops 19,
which helps in keeping the distal end of the main body 100 in the
centric part of the occlusion during device use. A device centrally
positioned in the occlusion plaque has less chance of trauma to
vessel walls and a higher chance of re-entry into the true lumen of
the vessel located distal to the CTO. In contrast, a device whose
distal end is positioned closer to the vessel wall has a higher
chance of vessel trauma leading to dissection and/or perforation of
the vessel wall. In addition, if the distal end of the device is
disposed eccentrically and close to the vessel wall, its chances of
re-entering the true lumen of the vessel is poor. If the device tip
is closer to the vessel wall the tip may also create a subintimal
dissection plane, which can advance within the vessel wall distal
to the CTO, instead of the intended reentry into the true vessel
lumen.
[0069] FIG. 1F illustrates the inner tubular member 11 without the
outer tubular member 10. Here, the wires 13, 14 can be seen in
double helix fashion around the inner tubule member, and forming
the outer loops 20 and distal loops 19 projecting from the inner
tubular member 11. When assembled, the outer loops 19 project from
the outer tubular member 10 and the distal loops project from the
distal cap 15 as illustrated in FIGS. 1A-1E.
[0070] In another embodiment of the device, a dilation balloon 52
envelops a portion of the main body 100 as depicted in FIGS. 2A and
2B. In a preferred embodiment, the balloon 52 is approximately 5.0
cm to 7.0 cm in length, between 5.0 mm and 6.0 mm in diameter, and
made of a polyethylene material. The balloon 52 is positioned over
the outer tubular member 10 around at approximately 1 cm proximal
to the outer loops 19. In this embodiment, the intertubular space
12 between the outer tubular member 10 and inner tubular member 11
is used as infusion lumen. The balloon 52 communicates with the
infusion lumen which extends to the proximal end of the main body.
When inflated with infusion media, the balloon 52 repositions the
distal end of the main body 100 toward a centric position inside
the vessel, and also dilates the passage made by the device inside
the CTO, thus facilitation stent placement.
[0071] FIGS. 3A-3D illustrate another embodiment of the main body
100 of the CTO device. The main body 100 is segmented into a
stationary unit 110 and a drilling unit 21. The drilling unit 21
spins when torque is applied to it via a torque transmitting member
26 which runs lengthwise through the lumen 38 of the main body 100.
The torque transmitting member 26 can be a solid or hollow wire,
tube, or shaft, made from a variety of materials, such as stainless
steel (SS 304) or similar compatible material. The torque
transmitting member 26 is coupled to the drilling unit 21 via a
coupler 27, which connects the drilling unit to the stationary unit
110, and forms the entire main body 100 of the CTO device. In one
embodiment, the drilling unit 21 is approximately between 2.0 and
4.0 cm in length. In a preferred embodiment, the drilling unit 21
is approximately 3.0 cm in length. The drilling unit 21 has the
features of the distal end of the embodiment illustrated in FIGS.
1A-1F. However, in the embodiment of the drilling unit 21 shown in
FIGS. 3A-C, there is no distal end cap hole 16 to allow a guidewire
to pass through the lumen 38 of the distal cap 15. The proximal end
of the drilling unit 21 is covered with proximal cap 42 and the
distal end of the stationary unit 110 is covered with a distal cap
40. The coupler 27 attaches to the proximal cap 42 on the drilling
unit 21 to connect the stationary unit 110 to the drilling unit
21.
[0072] One advantage of the segmented main body 100 embodiment of
FIGS. 3A-3C is that the drilling unit 21 spins independently of the
stationary unit 110, which does not spin when the torque
transmitting member 26 rotates. Since only the small drilling unit
21 spins, most of the main body 100 within the blood vessel remains
rotationally stationary, and thus does not produce any frictional
forces against inner wall of the blood vessel. Hence the operator
will have a better control over the exact location of the drilling
action of the device. This segmented main body 100 increases the
safety of the device and prevents unwanted force on non-occluded
areas of the blood vessel.
[0073] To accommodate a guidewire in this embodiment, a guidewire
tubular member 44 is located within the intertubular space 12 of
the stationary unit 110, which has a guidewire lumen 28. A
guidewire 39 can be passed through the guidewire lumen 28 and exits
the stationary unit 110 at guidewire exit hole 29, so the guidewire
can be used in later procedures. In one embodiment, the exit hole
29 is located between 0.5 and 5.0 cm proximal to the distal end
stationary unit 110. In a preferred embodiment, the exit hole 29 is
located approximately 1.0 cm proximal to the distal end of the
stationary unit 110. The helically coiled wires 13, 14 are
helically wrapped and secured around the stationary unit's inner
tubular member 11, and a second pair of wires 24, 25 is wrapped
around and secured to the inner tubular member 11 of the drilling
unit 21. In a preferred embodiment, a first wire 24 is helically
wrapped around the inner tubular member 11 and forms two of the
four loops 19, 20 (projecting from one outer tubular member hole
18, and one paracentral distal cap hole 17). A second wire 25 is
helically wrapped around the inner tubular member 11 and forms the
other two of four loops (projecting from the opposing outer tubular
member hole 18, and the opposing paracentral distal cap hole 17).
The loops 19, 20 on the distal unit 21 are brought out through the
holes 17, 18, and spot fixed as previously described in FIGS.
1A-1E.
[0074] FIG. 4 illustrates the proximal end of the stationary unit
110 of FIG. 3. The torque transmitting member 26 exits the proximal
end of the stationary 110 to attach to a motor unit, which applies
torque to the torque transmitting member 26. The guidewire tubular
member 44 has a guidewire entrance hole 30 for insertion of a
guidewire into the stationary unit 110.
[0075] FIGS. 5A and 5B illustrate a motor unit inner tubular member
31 and FIGS. 6A, 6B, 7A and 7B illustrate a motor unit outer tubule
member 32 that fits over the motor unit inner tubular member 31. An
assembled motor unit 130 illustrating an electric motor 36, inner
and outer motor unit tubular members 31, 32, attached to the main
body 100 of the device is illustrated in FIGS. 8A and 8B.
[0076] In a preferred embodiment, the inner tubular member of the
motor unit 31 is between approximately 15 cm and 20 cm in length
and disposed inside of the lumen 46 of the outer tubular member of
the motor unit 32, which in turn, is around 5 to 7 cm. The luminal
diameter of the motor unit inner tubular member 31 is approximately
0.5 mm to 1.0 mm larger than the diameter of the outer tubular
member of the main body 100 so that the motor unit 130 can easily
slide on the main body 100 as shown in FIGS. 7A and 7B. The outer
surface 33 of the motor unit inner tubule member 31 is threaded in
a helical configuration so that the so that the motor unit inner
tubule member 31 can fit inside of the motor unit outer tubule
member 32, which has a corresponding threaded inner surface 34 to
fit the motor unit inner tubule member 31. The motor unit inner
tubular member 31 can spin upwards or downwards within the outer
tubular member 32. The threaded configuration of the motor unit
tubule members 31, 32 converts part of the torque from an electric
motor 36 into linear motion, thus facilitating the advancement of
the distal end of the device through a CTO.
[0077] One embodiment of an electric motor has a gear system
configured to generate oscillatory curvilinear torque motion in the
rotor unit, which is attached to the main body 100. In one
embodiment the rotor unit in turn transmits the curvilinear
oscillatory motioning involving one third of a circle the main body
110 of the device. This pendulum-like motion of the main body 100,
when transmitted to the proximal end of the main body 100 or
drilling unit 21 will have less chance of plaque dislodgement and
distal embolization when compared to the spinning movement. The
motor unit 130 can be locked and unlocked with the main body via a
locking screw device 35, preferably made from a polyethylene
material, or the like.
[0078] The electric motor 36 may be a DC or AC motor having a
gear-box, the type being known by persons having skill in the art.
In use, the operator inserts the main body 100 into the blood
vessel through a small hole in the groin, and advances the distal
end of the main body 100 adjacent to a CTO 37, as shown in
exemplary form in FIG. 9. The motor unit 130 is inserted coaxially
over the main body 100 and advanced near to the skin entry point of
the main body 100. The motor unit inner tubular member 31 is then
locked to the main body 100 using a lock screw member 35. Then the
electric motor 36 is inserted coaxially over the main body 110,
advanced, and locked to the distal end of the motor unit inner
tubule member 31. The electric motor 36 is powered, and the
operator guides the inward and outward movement of the locked-in
combination of the motor unit inner tubule member 31 and main body
100. The torque created by the motor 36 and advancement of the
inner tubular member 31 within the outer tubule member 32 transmits
both linear and rotational movements to the distal end of the main
body 100. In the embodiment of FIGS. 1A-E, the motor unit 130
transmits rotational movement to the entire main body 110, while in
the embodiment depicted in FIG. 3A-D, the motor unit 130 is
connected to the torque transmitting device 26, and only transmits
rotational movement to the drilling unit 21.
[0079] As the main body 100 or the drilling unit 21 spins, the wire
loops 19, 20 in turn penetrate the proximal cap of the CTO and
advances, as shown in FIGS. 10A-C. After successfully crossing the
entire length of the occlusion 37, the operator confirms the
intraluminal position of the distal end of the main body 100
injecting small amount of radiopaque contrast though the guidewire
lumen under fluoroscopy guidance. Then the operator advances a
guidewire 39 though the device lumen 38 into the vessel lumen 48 as
shown in FIGS. 10C and 11.
[0080] In one embodiment of the device, the electric motor 36
rotates in a curvilinear oscillatory motion and does not comprise
the inner and outer motor tubular members 31, 32. Here, the
rotating axle of the electric motor 36 is attached directly to the
torque transmitting device 25 and torque would transmit directly
from the axle of the motor 36 to the drilling unit 21. In this
embodiment, the operator gives linear motion to the main body 100
with an inward push as the motor 36 is providing the torque to the
drilling unit 21 to fracture a CTO.
[0081] In the embodiment illustrated in FIGS. 8A and 8B, the
operator locks the motor 36 to the torque transmitting device,
advances the main body 100 gently into the blood vessel 48 and
through the CTO 37 while the rotor unit of the electric motor 36
rotates the drilling unit in a curvilinear fashion via the torque
transmitting device 26. Here, the operator adds the linear motion
of the curvilinear movement of the advancing tip of the main body
100 and drilling unit 21 at the distal end of the main body 100. In
this embodiment, the motor unit 130 is not used for linear motion
as the operator controls the forward motion of the main body
100.
[0082] FIG. 11 illustrates an exemplary embodiment of the device
shown in FIGS. 3A-D inside of vessel 50 that has passed through a
CTO 37. Here, the guidewire 39 exits the hole 29 located
approximately 1 cm proximal to the distal end of the stationary
unit 110. The guidewire 39 remains in the vessel lumen 48 after the
main body 100 is pulled out from the patient. The guidewire 39 can
then be used for further therapeutic interventions.
[0083] While all aspects of the present invention have been
described with reference to the drawings, this description of
various embodiments and methods shall not be construed in a
limiting sense. The aforementioned is presented for purposes of
illustration and description. It shall be understood that all
aspects of the invention are not limited to the specific
depictions, configures or relative proportions set forth herein
which depend on a variety of conditions and variables. The actual
dimensions and materials of a device constructed according to the
principles of the present invention may obviously vary outside of
the listed ranges and materials without departing from those basic
principles. The specification is not intended to be exhaustive or
to limit the invention to the precise forms disclosed herein.
Various modifications and insubstantial changes in form and detail
of the particular embodiments of the disclosed invention, as well
as other variations of the invention, will be apparent to a person
skilled in the art upon reference to the present disclosure. It is
therefore contemplated that the appended claims shall cover any
such modifications or variations of the described embodiments as
falling within the true spirit and scope of the invention.
* * * * *